Terahertz optical-Hall effect characterization of two-dimensional electron gas properties in AlGaN/GaN high electron mobility transistor structures

Authors

• S. Schöche, University of Nebraska–LincolnFollow
• Junxia Shi, Cornell University
• A. Boosalis, University of Nebraska–Lincoln
• P. Kühne, University of Nebraska–Lincoln
• C. M. Herzinger, J.A. Woollam Co. Inc.
• John A. Woollam, J.A. Woollam Co. Inc.Follow
• W. J. Schaff, Cornell University
• L. F. Eastman, Cornell University
• M. Schubert, University of Nebraska–LincolnFollow
• Tino Hofmann, University of Nebraska–LincolnFollow

Document Type

Article

Date of this Version

2011

Citation

APPLIED PHYSICS LETTERS 98, 092103 (2011); doi:10.1063/1.3556617

Comments

Copyright 2011 American Institute of Physics

Abstract

The free-charge carrier mobility, sheet density, and effective mass of a two-dimensional electron gas are exemplarily determined in the spectral range from 640 GHz to 1 THz in a AlGaN/GaN heterostructure using the optical-Hall effect at room temperature. Complementary midinfrared spectroscopic ellipsometry measurements are performed for analysis of heterostructure constituents layer thickness, phonon mode, and free-charge carrier parameters. The electron effective mass is determined to be (0.22 ± 0.04)m₀. The high-frequency sheet density and carrier mobility parameters are in good agreement with results from dc electrical Hall effect measurements, indicative for frequency-independent carrier scattering mechanisms of the two-dimensional carrier distribution.